The Flobert cartridge, also known as a .22 CB Cap (Conical Ball Cap) cartridge, is a variety of .22 caliber rimfire ammunition which has a very small propellant charge (usually no gunpowder, just the primer), resulting in a low muzzle velocity. The Flobert cartridge has a similar muzzle velocity as is produced by a low to mid-power .22 pellet gun, however the bullet from a .22 CB cartridge is significantly heavier than a typical air gun pellet and therefore carries more energy.
Flobert cartridge guns produce less noise than most guns and are useful where a low power cartridge is desirable, for example, in pest control or indoor target shooting. The .22 CB cartridge has not been popular in the United States, but has remained somewhat popular in Eastern Europe. In some countries, .22 CB weapons are in the category of air guns, so are not subject to gun laws. In recent years, there has been renewed interest in Flobert cartridge weapons as low cost training weapons and recreational shooting weapons with a minimal cost per shot.
As a training weapon for handling semi-automatic pistols, a Flobert cartridge pistol may be desirable as a low cost, low power weapon. A true semi-automatic pistol has a slide that is forced backwards from the recoil on firing a round. The backward action ejects the spent cartridge, and typically cocks the hammer for the next shot. A spring forces the slide back to its originally position. The return action strips a new cartridge from the ammunition magazine and chambers the round, ready for the next shot with the hammer cocked. However, the relatively small propellant charge of Flobert cartridges does not generate sufficient energy to force the slide back against the spring, eject the spent cartridge, cock the hammer for a new shot, and strip and chamber a new cartridge from an ammunition magazine.
In typical semi-automatic pistols, the hammer is cocked by the recoil action of the slide, so each trigger pull subsequent to the first shot is single action, meaning that the trigger only releases the cocked hammer. In a double action trigger pull, the first part of the trigger pull cocks the hammer, and a second step in the trigger pull releases the hammer to fire the shot. Most modern semi-automatic pistols have a double action trigger pull feature for the first round.
In some semi-automatic pistols, the slide recoil does not cock the hammer Thus, each trigger pull is double action, also called “double-action only.” Examples of such weapons include the Kel-Tec P-11 and Sig Sauer P290RS Nitron Sub-Compact.
Most Flobert cartridge weapons available on the market are revolvers. Some of them are styled as Flobert cartridge pistols, but actually have a small revolver drum, which is characteristic for revolvers. For examples, see http://gunmag.com.ua/pistolety-pod-patron-flobera-pervye-shagi and the PMF-1 Makarov pistol (http://guns-review.com/documents/review.php?entry_id=1405415205).
Other Flobert cartridge weapons styled as pistols do not have semi-automatic functions. For example, the “P1F ULTRA MK7/1” pistol uses bullet-shaped sleeve that each Flobert round must be inserted into (http://www.commando.sk/zbrane/flobert-4 mm-6 mm/flobert-6 mm/grand-power-plf-ultra-mk71-flobert-pistol-6 mm) This weapon also requires the user to manually pull the slide back after each discharge. That is, this pistol has no semiautomatic functions, making such pistols unsuitable for field firing practices.